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Three new hot hydrogen-deficient pre-white dwarfs
Werner, Klaus; Reindl, Nicole; Geier, Stephan +1 more
We have detected three new hydrogen-deficient (H < 0.001 mass fraction) pre-white dwarfs (WDs) with helium-dominated atmospheres. The first object is a relatively cool PG1159 star (effective temperature Teff = 72 000 K) that has the lowest surface gravity of any PG1159 star known (log g = 4.8). It is a PG1159 star in the earliest pre…
Evolution of X-Ray Gas in SN 1987A from 2007 to 2021: Ring Fading and Ejecta Brightening Unveiled through Differential Emission Measure Analysis
Greco, Emanuele; Vink, Jacco; Miceli, Marco +4 more
As the nearest supernova (SN) observed since Kepler's SN of 1604, SN 1987A provides an unprecedented opportunity to study in detail the early evolution of supernova remnants. Despite extensive studies through both observations and simulations, there is still an urgent need for a more effective approach to integrate the results from two sides. In t…
Investigating the formation of small Solar System objects using stellar occultations by satellites: present, future and its use to update satellite orbits
Sicardy, B.; Desmars, J.; Braga-Ribas, F. +2 more
The history of the outer solar system is intrinsically related to the Giant Planets migration. A massive disk of material within a radius of 30 au was scattered during the planetary migration, creating different dynamic populations in the Transneptunian region. They were formed in a collisional environment when massive collisions allowed them to g…
LEIA Discovery of the Longest-lasting and Most Energetic Stellar X-Ray Flare Ever Detected
Shi, Jianrong; Lin, Jun; Deng, Licai +40 more
The Lobster Eye Imager for Astronomy (LEIA) detected a new X-ray transient on 2022 November 7, identified as a superflare event occurring on a nearby K-type giant star HD 251108. The flux increase was also detected in follow-up observations at X-ray, UV, and optical wavelengths. The flare lasted for about 40 days in soft X-ray observations, reachi…
Resolving the mass transfer in the symbiotic recurrent nova T Coronae Borealis
Jorissen, A.; Planquart, L.; Van Winckel, H.
Context. T Coronæ Borealis (T CrB) is a symbiotic recurrent nova with an 80-year recurrence interval whose next eruption is imminent. Aims. We aim to resolve the accretion mechanism of the binary system governing the mass transfer during its super-active phase. Methods. Using phase-resolved high-resolution spectroscopy, we analyzed the zoo of spec…
Ultraviolet Photometry and Habitable Zones of over 2700 Planet-hosting Stars
Liu, Jifeng; Wang, Song; Li, Xue +1 more
The ongoing discovery of exoplanets has sparked significant interest in finding suitable worlds that could potentially support life. Stellar ultraviolet (UV; 100–3000 Å) radiation may play a crucial role in determining the habitability of their planets. In this paper, we conducted a detailed analysis of the UV photometry of over 2700 host stars wi…
Ion Charge States from a Global Time-dependent Wave-turbulence-driven Model of the Solar Wind: Comparison with in Situ Measurements
Riley, Pete; Rivera, Yeimy J.; Lionello, Roberto
Solar wind charge-state measurements contain a wealth of knowledge related to the properties of the solar corona from where they originated. However, their interpretation has remained challenging because it convolves coronal temperature, density, and velocity along the particles' trajectory through the corona before they "freeze in" and are convec…
Distribution functions for the modelling of accretion remnants in Milky Way-like galaxies: insights from IllustrisTNG
Bovy, Jo; Lane, James M. M.
We study accretion remnants around Milky Way analogues in the IllustrisTNG simulations to determine how well commonly used distribution functions (DFs) describe their phase-space distributions. We identify 30 Milky Way analogues and 116 remnants from mergers with stellar mass ratios greater than 1:20. Two power density profiles, as well as rotatin…
MAGIS (Measuring Abundances of red super Giants with Infrared Spectroscopy) project: I. Establishment of an abundance analysis procedure for red supergiants and its evaluation with nearby stars
Kobayashi, Naoto; Matsunaga, Noriyuki; Kawakita, Hideyo +11 more
Context. Given their high luminosities (L ≳ 104 L⊙), red supergiants (RSGs) are good tracers of the chemical abundances of the young stellar population in the Milky Way and nearby galaxies. However, previous abundance analyses tailored to RSGs suffer some systematic uncertainties originating in, most notably, the synthesized …
Stereoscopic observations reveal coherent morphology and evolution of solar coronal loops
Peter, H.; Chitta, L. P.; Plaschke, F. +2 more
Coronal loops generally trace magnetic lines of force in the upper solar atmosphere. Understanding the loop morphology and its temporal evolution has implications for coronal heating models that rely on plasma heating due to reconnection at current sheets. Simultaneous observations of coronal loops from multiple vantage points are best suited for …